Re: Hammer, usb disk, SYNCHRONIZE CACHE failure

To:

Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx>

From:

Michael Neumann <mneumann@xxxxxxxx>

Date:

Wed, 08 Apr 2009 22:50:09 +0200

Followup-to:

dragonfly.bugs

Matthew Dillon wrote:
>
> :This is for 2.2-RELEASE. I have a 2.5" drive in an external USB
> :enclosure with one big Hammer filesystem on it. The disk is ~75GB.
> :When the daily cronjob to cleanup hammer runs it fails with these
> :errors:
> :
> :Thanks,
> :Joe
>
> I'm not sure what's going on here. HAMMER does issue a synchronize
> cache
> op but it should be ignoring the error. Maybe the recovery from the
> unsupported synchronize cache op is causing a later write op to fail.
I think there are devices that claim to support this operation but in
reality do not support it. Or something like this. FreeBSD has a quirk file
for this. For example my Seagate USB disk always prints those synchronize
cache failure messages on FreeBSD. Look out for NO_SYNCHRONIZE_CACHE
in this file:
http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/dev/usb/storage/umass.c?rev=1.9
Regards,
Michael